Add new line to custom Exception message in Anypoint Studio Mule

I am using Anypoint Studio 6.1 and Mule 3.8.1 and want to return an Exception message with the "\n" returned as a new line. I am trying to use System.getProperty("line.separator") but the "\n" still appear in the message as text and not a new line.

How can I get this to work?

XML Test Flow:

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
    xmlns:spring="http://www.springframework.org/schema/beans" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd">
    <flow name="tempflowFlow">
        <http:listener config-ref="HTTP_Listener_Configuration" path="/test-flow" allowedMethods="GET" doc:name="HTTP"/>
        <set-payload value="{
  &quot;Exception&quot;: {
    &quot;status&quot;: -1,
    &quot;description&quot;: &quot;\nJson content is not compliant with schema\ncom.github.fge.jsonschema.core.report.ListProcessingReport: failure\n--- BEGIN MESSAGES ---\nerror: object has too many properties (found 2 but schema requires at most 1)\n    level: \&quot;error\&quot;\n    schema: {\&quot;loadingURI\&quot;:\&quot;file:/C:/temp.json#\&quot;,\&quot;pointer\&quot;:\&quot;/properties/field1\&quot;}\n    instance: {\&quot;pointer\&quot;:\&quot;/field1\&quot;}\n    domain: \&quot;validation\&quot;\n    keyword: \&quot;maxProperties\&quot;\n    found: 2\n    required: 1\n---  END MESSAGES  ---\n (org.mule.module.json.validation.JsonSchemaValidationException).&quot;
  }
}" encoding="UTF-8" mimeType="application/json" doc:name="Set Payload"/>
        <logger message="#[payload.replace(&quot;\n&quot;, System.getProperty('line.separator'))]" level="INFO" doc:name="Logger"/>
        <set-payload value="#[payload.replace(&quot;\n&quot;, System.getProperty('line.separator'))]" encoding="UTF-8" mimeType="application/json" doc:name="Set Payload"/>
    </flow>
</mule>

Thanks

Looks like you need to escape the newline character. Also, use single quotes (') instead of double quotes (") inside MEL expression.

<logger message="#[payload.replace('\\n', System.getProperty('line.separator'))]" level="INFO"
        doc:name="Logger" />
    <set-payload value="#[payload.replace('\\n', System.getProperty('line.separator'))]" encoding="UTF-8"
        mimeType="application/json" doc:name="Set Payload" />

Above code seems to work:

INFO  2017-02-09 18:03:09,349 [Mule.app.deployer.monitor.1.thread.1] org.mule.module.launcher.MuleDeploymentService: 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ Started app 'test2'                                      +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
INFO  2017-02-09 18:03:17,280 [[test2].HTTP_Listener_Configuration.worker.01] org.mule.api.processor.LoggerMessageProcessor: {   "Exception": {     "status": -1,     "description": "
Json content is not compliant with schema
com.github.fge.jsonschema.core.report.ListProcessingReport: failure
--- BEGIN MESSAGES ---
error: object has too many properties (found 2 but schema requires at most 1)
    level: \"error\"
    schema: {\"loadingURI\":\"file:/C:/temp.json#\",\"pointer\":\"/properties/field1\"}
    instance: {\"pointer\":\"/field1\"}
    domain: \"validation\"
    keyword: \"maxProperties\"
    found: 2
    required: 1
---  END MESSAGES  ---
(org.mule.module.json.validation.JsonSchemaValidationException)."   } }

Mule log